$4.93 seems like the MAXIMUM price for a Big Mac in the U.S., not the average, except perhaps in New York City. I would guess that these sandwiches are purchased as part of a value meal at least 75% of the time. Packaged this way the unit price of the Big Mac is much lower than as a standalone purchase. If the Big Mac price of the comparison countries is inflated the same way as the U.S. price is, there is no harm. But I doubt it.

Another factor which applies to Europe and Japan, is that many large companies have reached their maximum production capacity, as they have reduced a lot their investments since 2008. They have to invest first in new facilities before starting to export.

I do agree with the comment of LiberalWorld: "Everybody's currency is down versus the dollar, so unless the Americans start buying everyone's production, nobody is going to benefit from weaker currencies." Yes, that's the point.

I also think that the Big Mac Index is not relevant to countries which export only commodities, like Russia and Indonesia. I have noticed that in Indonesia, if you convert the price in euros, the cost of living has followed the inflation rate for at least the last 10 years, while the big mac index suggests that indonesian rupiah is largely undervalued.

Another factor at play which applies to economies with weak manufacturing industries and which rely on imported components and sub-systems, is that when the exchange rate drops, the cost of these inputs increase and the competitive position of manufacturing ends up not as favourable as what might be expected.

In considering the reported increase in Australia's manufacturing output in 2015, one would be advised to determine in which sectors this has occurred. It is suspected that there has been little increase in hi-tech manufactures areas, which currently represent a small contribution to Australia's overall exporting results.

The government in Argentina forces Arcos Dorados (who has the local concession of McDonadls in Latin America) to have a signifcat price discount on the Big Mac just to appear in a favourable way in the Big Mac Index. Would not be surprised at all if this arrangament extends to other Latam countries... Currencies might appear undervalued in the chart when that is not the case in several markets.

Unfortunately, this article has been quoted in the Russian propaganda quite a few times today. This state-controlled media especially enjoyed the starting message about "Russian Ruble being undervalued at 64%". This message and an article itself became a major talking point on the Russian TV today as well.
I do not think that Russian Ruble is undervalued at all. In fact, it may be sliding further down against major international currencies due to hazardous and adventurous policies developed by their leaders, accepted by their government and "officially" supported by over 85% of the Russian population. These policies include for example public discussion of preventive nuclear attack against Western countries, mockery of the EU humanitarian policies, especially in reference to Middle Eastern and South African refugees, humiliation of any political activities, any statements made by POTUS, personal and racially based attacks on him personally, disregard to European borders, etc.

The fiat currency, by definition, has no intrinsic value, hence there can be no intrinsic over or under valuation, as the bigMac index purportedly to show. Everything is relative (or as bible says: "meaningless, meaningless, everything is utterly meaningless!").

The real concern is that dollar is way, way overvalued (relative to other major currencies).

While your choice of a Big Mac as an International NGC (Non-Governmental Currency) seems to have rolled everything up in a bun, there is still another global yardstick out there with potential: "The Starbuck."
A comparison of the two might offer a jolt and bring things down to Earth.

While this is technically true by the definitions you have given, "overvalued" and "undervalued" are meaningless except in relative terms.

For example, the Canadian dollar is overvalued relative to the majority of currencies included in the chart. However, it is undervalued relative to its primary trade partner, the US. As a result, it is far more practical to think of it as an undervalued currency than an overvalued one.

@Hui Shi: While what you've written might be true, it only pertains to Canada, Mexico and some minor Caribbean islands. Your argument is irrelevant to the discussion concerning the Big Mac Index and the majority of Earth's countries.

In southern Ontario Canada, years of a high Canadian dollar did great damage to our manufacturers especially automotive. A number of auto and truck makers closed plants. Major auto production declined massively in 5 years. Now as the Canadian dollar is weak, the smaller nimble parts suppliers are having great business. The major auto and truck manufacturers are increasing production at their facilities that are still open here, but no new car plants are being built. The recover is underway but for mostly poorer paying supplier jobs. Things have rebounded but will not be as they once were. We are in too much competition from Mexico and the southern US. Other industries will need to be established and grown if we are to succeed in the global game.
Hurrah for cheap big Mac's and beer- that will be our "big night out" for a while yet.